2.087*d2+1982.75*d-3000000=0

Solution for 2.087*d2+1982.75*d-3000000=0 equation:

2.087d^2+1982.75d-3000000=0

a = 2.087; b = 1982.75; c = -3000000;
Δ = b2-4ac
Δ = 1982.752-4·2.087·(-3000000)
Δ = 28975297.5625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1982.75)-\sqrt{28975297.5625}}{2*2.087}=\frac{-1982.75-\sqrt{28975297.5625}}{4.174}
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1982.75)+\sqrt{28975297.5625}}{2*2.087}=\frac{-1982.75+\sqrt{28975297.5625}}{4.174}
$